Human Reproduction

1. Human Reproduction Health- Davenport

2. Puberty • Human reproduction is controlled by hormones secreted by the gonads (testes and ovaries). • Puberty • Male Hormone- Testosterone • Female Hormones- Estrogen and Progesterone • These changes are called secondary sex characteristics. • Males usually reach puberty at about 12-14. • Females usually reach puberty between the ages of 10-14.

3. Secondary Sex Characteristics • Female • Development of breasts (mammary glands) • Changes in body form • Growth of body hair • Male • Growth of beard and other body hair • Changes in body form • Lowered voice pitch

4. Male Reproductive System • Two major functions: • Production of sperm • Deposition of sperm inside the female reproductive tract. • The production of sperm takes place in a pair of male gonads called the testes. • The testes are held in a sac called the scrotum. • The scrotum keeps the temperature of the testes one or two degrees (C) cooler than normal body temperature. • This lower temperature is necessary for sperm production and storage.

5. Male Reproductive System

6. Female Reproductive System • The Female Reproductive System produces eggs (ova) and is the site of fertilization and embryonic development. • The production of eggs takes place in paired gonads called ovaries. • The ovary produces eggs in structures called follicles. • Follicles are tiny cavities surrounded by cells. • The release of a mature egg from a follicle is called ovulation.

7. Female Reproductive System • Following ovulation, the egg passes through an oviduct (fallopian tube). • Then the egg moves to the uterus. • The uterus, or womb, is shaped like a pear and has thick walls. • The embryo develops in the uterus. • The lower end of the uterus, the cervix, opens into a muscular tube called the vagina. • The vagina is a muscular tube that leads from the uterus to the outside.

8. Female Reproductive System

9. Male/Female Reproductive System Worksheets Please get a health book “Core Concepts in Health” and turn to pages 125-126 to fill in the parts of a male and female reproductive system.

10. The Journey of Sperm Sperm are produced inside the testes. As they mature they are stored in a tube known as the epididymis, which lies on the surface of each testis. Sperm move from each epididymis into another tube called the vas deferens.

11. The Journey of Sperm… 4. The two vas deferens merge into a pair of seminal vesicles, whose secretions provide nutrients for the sperm.

12. The Journey of Sperm… 5. The sperm then mix with a milky fluid from the Prostate Gland and Cowpers Glandand become semen.

13. The Journey of Sperm… 6. On the final stage of their journey, semen flow into ejaculatory ducts where they are then released during ejaculation through the urethra.

14. Cowper's gland

15. The Menstrual Cycle • Once a month an ovum is released • Ovum- a female egg • The egg moves through the fallopian tube to the uterus • Uterus- where the baby develops during pregnancy • If the egg does not become fertilized, it disintegrates and is flushed away with menstruation

16. The Menstrual Cycle • The menstrual cycle usually begins in females between the ages of 10 and 14 • It is repeated approximately every 28 days • During the cycle the walls of the uterus thicken preparing for reproduction • The menstrual cycle stops during pregnancy • The cycle starts at puberty and ends at menopause

17. But . . . • If it is fertilized in the Fallopian Tube by a sperm—Conception occurs • This Union of the sperm and egg is what we call a zygote!

18. Fertilization

19. Fertilization • If more than one egg is released and fertilized at the same time, multiple births may occur. • Fraternal twins develop when two eggs are released at one time and each egg is fertilized by a different sperm. • Identical twins develop from one zygote that separates in half early in cleavage. • It is now possible for fertilization to take place outside the human body (in vitro). The fertilized egg is then implanted in the uterus so that development can occur.

20. PrenatalDevelopment- The Zygote • When the fertilized egg arrives in the uterus, it implants itself in the thickened, spongy uterine wall. • Differentiation of cells and growth occurs. • The developing embryonic membranes become part of the placenta and umbilical cord • Placenta- The tissue that connects the sac around the unborn baby to the mother’s uterus • Umbilical Cord- Tube that connects the baby to the placenta • Brings the baby nourishment and oxygen from the mother’s blood • Takes away waste products

21. Two Cells Four Cells Fertilization Implantation Blastocyst Stage 16 Cells Morula Stage The Human Zygote

23. Development- Fetus • The embryo develops in the Amniotic Sac • Amniotic Sac- the fluid-filled sac that contains and protects a fetus in the womb • After eight weeks of development the embryo is called the Fetus. • The period of time between the fertilization of the egg and the birth of the offspring is called gestation • In humans, the gestation period is nine months or approximately 266 days.

24. Human Gestation- The carrying of an Embryo/Fetus 3 Weeks

25. Human Gestation 3 Months

26. Summary of Human Development

27. Prenatal Development • During this time, it is essential that the expectant mother provide good prenatal care by eating nutritious foods, avoiding alcohol, tobacco, and drugs, and receiving proper medical attention regularly. • Using tobacco, alcohol and drugs may cause low birth rates, premature births, Fetal Alcohol Syndrome as well as other birth defects.

28. Postnatal Development • Following birth, the placenta is discarded from the mother’s body and the mother begins producing milk from mammary glands located in the breasts. • The mother’s breast milk is normally the best natural food for a newborn baby.

29. The First Trimester The nine months of pregnancy are divided into three periods, known as Trimesters. Each trimester is 3 months long. In the First Trimester, while the embryo is developing into a fetus, the mother may experience morning sickness. Morning sickness consists of attacks of nausea and sometimes vomiting. The cause is related to changes in the levels of certain hormones that occur as a result of the pregnancy. Morning sickness usually disappears after the first few weeks. Other changes that occur during the first trimester are: increase in breast size and tenderness, frequent urination, overwhelming tiredness.

30. The Second Trimester The mothers abdomen begins to swell and she can feel movements of the fetus. As the fetus and placenta grow, the enlarged uterus pushes against the mothers digestive tract. This can cause constipation or indigestion. Toward the end of the second trimester, a thin fluid may begin to leak from the nipples. This fluid is the forerunner of breast milk.

31. The Third Trimester Most women gain between 25-35 pounds during pregnancy. As the fetus grows to its birth size, its movements can be seen and felt on the mothers abdomen. Some contractions can be felt, the uterus is preparing its muscles for the work of pushing the fetus out.

32. Menopause • hot flashes • vaginal dryness • low libido • painful intercourse • night sweats • insomnia • thinning hair • mood changes As a woman approaches age 50, her ovaries gradually cease to function and she enters menopause, the cessation of menstruation. For some women, the associated drop in hormone production causes troublesome symptoms such as: